1. Field of the Invention
The present invention relates to a projector-type vehicular headlamp.
2. Description of the Related Art
Generally, in a projector-type vehicular headlamp, a projector lens is disposed on an optical axis that extends in the longitudinal direction of a vehicle, and a light source is provided on the rear side of the rear side focal point of the projection lens so that light from the light source is reflected by a reflector toward the optical axis.
FIG. 9 shows a conventional example of this type of projector-type vehicular headlamp.
The vehicular headlamp 101 of FIG. 9, disclosed in U.S. Patent Application Publication No. US 2005/0190572 A1, includes a projection lens 102 that is disposed on an optical axis Ax extending in the longitudinal direction of the vehicle, a light source bulb 103 that is provided on the rear side of behind the rear side focal point F of the projection lens 102, a reflector 104 that reflects direct light from the light source bulb 103 forward and toward the optical axis Ax, and an additional lens 105 that is mounted in the form of a ring around the outer perimeter of the projection lens 102.
The additional lens 105 directs light, which is radiated from the light source bulb 103 to the outer perimeter of the projection lens 102, forward in a form of light that is roughly parallel to the optical axis Ax.
When an ordinary projector-type vehicular headlamp is lit, light is emitted from and visible through only the projection lens. However; as shown in FIG. 9, if the additional lens 105 is provided around the outer perimeter of the projection lens 102, the light-emitting surface area of the entire lamp can be enlarged to such an extent that the additional lens 105 directs the light forward. Accordingly, the lamp has an increased better visibility to drivers of oncoming vehicles and the like, thus improving safety when the vehicle is running.
However, the additional lens 105 used in the lamp of FIG. 9 is a lens that forwardly directs light which reaches the outer perimeter of the projection lens 102 and is thus not utilized by or enter the projection lens 102. As a result, the additional lens 105 does not direct light to the side of the vehicle.
Thus, the problem with this lamp is that it cannot contribute to enhance the visibility of the vehicle to the pedestrians or the like who are on the lateral side of the vehicle.